Please help with pullet leg injury (pics)

My 13-week-old Rhode Island Red pullet has been limping for a week. My first guess was rickets, but I am starting to doubt that diagnosis because the limp seems limited to one leg, and her beak and nails seem strong and healthy.

What made me think it might be rickets initially is that she's been lagging behind my other chicken--who is the same age and breed--in development. (My other chicken is bigger, more energetic, has thicker legs and has a bigger, redder comb and wattles.)

Today, I noticed that my limping chicken has lost of feathers right at the top of her injured leg (where the feathers start). Here is a photo of the area:

I looked closely and didn't see any mites or other bugs. My first guess would be that she's picking at the area herself, or that she scraped it on the slats in the coop when she got her leg stuck between them on Monday. But honestly, I am a chicken-owning newbie, so I have no idea of this is a really serious injury or not.

There's no blood that I can see, just a bluish tint to some of the feather pins that are left. Just in case, I swabbed the area with Neosporin this afternoon.

I have also been giving this chicken liquid children's multi-vitamin by beak once a day. This started when I suspected rickets.

Other than her limp, my hurt chicken seems fine. She's eating and drinking normally, and comes out of the run to free range with her sister, although she sits down a lot when she's out and about.

Can someone give me any insight into what might be wrong?

I don't think she has mites, but I'm not certain. I haven't seen any bugs on her, and she takes dust baths frequently.

Here are some more photos for reference.

Bottom of foot on injured leg:

Injured leg:

My injured chicken's face, in case you want to see her eye and comb condition:

Quote:No. I have been trying to watch and see if my other pullet has been aggressive or picking at the hurt one at all, and she's not. I have seen her take interest in a few of the injured ones dirty wing feathers, but it seemed like she was grooming not pulling. Other than that, she's been perfectly nice to the hurt one, at least in public.